Algebra Word Problem #2
Please help me find the answer for this.
Alex can run 5 mph on level ground on a still day. One windy day, on which the wind blew at a consistent rate all day, he ran 11 miles on level ground with the wind and in the same amount of time ran 4 miles on level ground against the wind. What is the speed of the wind?

Thank you for your consistent help, Sarosh.
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